Not Applicable
Not Applicable
This invention relates to implantable medical devices and delivery systems for delivering such medical devices into a body lumen.
Percutaneous transluminal coronary angioplasty (PTCA) is a procedure which is well established for the treatment of blockages in the coronary arteries. Blockages may occur from cholesterol precipitation on the coronary wall which may be in any stage from initial deposit through aged lesions. Coronary arteries may also become blocked due to formation of thrombus.
The most widely used form of percutaneous coronary angioplasty makes use of a dilatation balloon catheter which is introduced into and advanced through a lumen or body vessel until the distal end thereof is at a desired location in the vasculature. Once in position across a lesion site, the expandable portion of the catheter, or balloon, is inflated to a predetermined size with a fluid at relatively high pressures, to radially compress the atherosclerotic plaque of the lesion against the inside of the artery wall and thereby dilate the lumen of the artery. The balloon is then deflated to a small profile so that the dilatation catheter may be withdrawn from the patients vasculature and blood flow resumed through the dilated artery.
In angioplasty procedures of the kind described above, there may be restenosis of the artery, which either necessitates another angioplasty procedure, a surgical by-pass operation, or some method of repairing or strengthening the area. To reduce restenosis and strengthen the area, a physician can implant an intravascular prosthesis for maintaining vascular patency, such as a stent, inside the artery at the lesion.
Expandable, implantable medical devices such as stents are utilized in a number of medical procedures and situations as are stent delivery assemblies. As such, their structure and function are well known. A stent is a generally cylindrical prosthesis introduced via a catheter into a lumen of a body vessel in a configuration having a generally reduced diameter and then expanded to the diameter of the vessel. The stent may be self-expanding, such as a nitinol shape memory stent, or it may be expandable by means of an inflatable portion of the catheter, such as a balloon. In its expanded configuration, the stent supports and reinforces the vessel walls while maintaining the vessel in an open, unobstructed condition.
Some stents have been developed specifically to address the problems that arise in the treatment of stenoses at or near the site of a bifurcation of a body lumen are known in the art. Further, single bifurcated stents and grafts have been developed in order to treat such conditions at the site of a branch of a body lumen. A bifurcated stent and/or graft typically comprises a tubular body or trunk and two tubular legs. Examples of bifurcated stents are shown in U.S. Pat. No. 5,723,004 to Dereume et al., U.S. Pat. No. 4,994,071 to MacGregor, and U.S. Pat. No. 5,755,735 to Richter, et al.
Various techniques have been used to deliver multiple prostheses in order to provide radial support to both a main blood vessel, and contemporaneously to side branches of the blood vessel. Examples of catheters for use in treating bifurcated lumens or delivery systems for bifurcated stents, are shown in U.S. Pat. No. 5,720,735 to Dorros, U.S. Pat. No. 5,669,924 to Shaknovich, U.S. Pat. No. 5,749,825 to Fischell, et al., U.S. Pat. No. 5,718,724 to Goicoechea et al., and U.S. Pat. No. 6,129,738 to Lashinski et al. As maybe seen from these references, in most bifurcated stent delivery systems, the bifurcated stent is mounted on a catheter assembly which comprises essentially two balloon catheters mounted in a guide catheter assembly.
Bifurcated stents such as described above are often more bulky than a cylindrical stent having no branches. The delivery systems for use with bifurcated stents are likewise often more bulky than many of those systems for use in delivering branchless cylindrical stents. The delivery systems for such branchless cylindrical stents may also be somewhat less complex than those utilized with bifurcated stents.
A single branchless cylindrical stent however, may be unsuited for treatment of bifurcation. It would be preferable to utilize multiple cylindrical stents that could be placed in and around a bifurcation site to effectively form a stent assembly which functions similarly to a single bifurcated stent. While use of such multiple stent assemblies would avoid the problems associated with bifurcated stents and delivery systems, delivery of multiple stents to a site within the body could be a difficult undertaking requiring several catheters to be sequentially advanced through a vessel or vessels, in order to place each stent at or around the bifurcation. Moreover, by advancing multiple catheters through the body the risk of damaging the vessel(s) through which each of the delivery catheters is advanced is inherently increased.
In light of the above it would be desirable to provide a multiple stent catheter assembly for treatment of a bifurcation or other region of a vessel, which could be readily inserted into the vessel with a single catheter application.
All U.S. patents, applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
This invention relates to a unique stent assembly and delivery system. A stent assembly comprises at least two stents for delivery into one or more predetermined locations in a body lumen, such as a bifurcation of a vessel and surrounding area. In delivering the stent assembly, the stent assembly may be disposed about a portion of a delivery catheter in an at least partially overlapping configuration. Between each stent may be positioned one or more retractable sheaths or sleeves. The outer most stent may also have a retractable sleeve disposed thereabout. The unique configuration of stents and retractable sleeves provides for the ability to utilize a single catheter to deliver multiple stents to one or more locations in a body lumen.
In some embodiments of the invention, a stent delivery catheter is provided for which comprises an inner member having a first stent disposed thereabout and a second stent disposed about the first stent. The catheter further comprises a first sheath between the first stent and the second stent and may have a second sheath disposed about the second stent. The catheter may be configured to deliver stents of any type including self-expandable and balloon expandable stents. The catheter may be further configured to deliver more than two stents and sheaths. The catheter may be used to deliver stents of different types as well as different sizes.
In some other embodiment of the invention a method of treating a body is provided for which comprises the steps of providing a catheter comprising a plurality of stents including a first stent and a second stent, the first stent extending within the second stent; inserting the catheter in a bodily vessel and delivering the stents to a first desired location within the body; deploying one of the first and second stents at the first desired location; delivering the other of the first and second stents to a second desired location within the body, the second desired location different than the first desired location; deploying the other of the first and second stents at the second desired location.
Further aspects of the invention will become apparent from the detailed description which follows.